Turn SkTaskGroups back on.

Turn SkTaskGroups back on.

Revert "Disable SkTaskGroup in SkMultiPictureDraw temporarily."
Revert "Revert harder, removing SkTaskGroup.cpp from core temporarily."

NOTREECHECKS=true

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/2100c5ed7a5e5470a04e7af7309d8bd3fc4249f7

Committed: https://skia.googlesource.com/skia/+/ecf987559b1db0cb3fcaccdde2a065e4391d9b60

[mtklein, 2014-10-30 17:06:15]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2014-10-30 17:06:46]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/687263007/1

[commit-bot: I haz the power, 2014-10-30 17:06:47]

Note for Reviewers:
The CQ is waiting for an approval.
If you believe that the CL is not ready yet, or if you would like to L-G-T-M
with comments then please uncheck the CQ checkbox.

Waiting for LGTM from valid reviewer(s) till 2014-10-30 23:06 UTC

[commit-bot: I haz the power, 2014-10-30 23:06:57]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-10-30 23:06:58]

No LGTM from a valid reviewer yet. Please ask for an LGTM from a
full Skia committer from
https://skia.googlesource.com/skia/+/master/CQ_COMMITTERS

[reed1, 2014-10-31 12:17:18]

reed@google.com changed reviewers:
+ reed@google.com

[reed1, 2014-10-31 12:17:19]

lgtm

[mtklein, 2014-10-31 13:33:18]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2014-10-31 13:33:41]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/687263007/1

[mtklein, 2014-10-31 13:38:08]

The CQ bit was unchecked by mtklein@google.com

[mtklein, 2014-10-31 13:38:12]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2014-10-31 13:38:15]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/687263007/1

[commit-bot: I haz the power, 2014-10-31 13:38:30]

Committed patchset #1 (id:1) as 2100c5ed7a5e5470a04e7af7309d8bd3fc4249f7

[mtklein, 2014-10-31 18:29:45]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/693993002/ by mtklein@google.com.

The reason for reverting is: precautionary revert.  may have caused WinXP
crashes on Chrome tree:
https://code.google.com/p/chromium/issues/detail?id=429207.

[mtklein, 2014-11-04 01:40:30]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2014-11-04 01:40:59]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/687263007/1

[commit-bot: I haz the power, 2014-11-04 01:41:18]

Committed patchset #1 (id:1) as ecf987559b1db0cb3fcaccdde2a065e4391d9b60